1. Field of the Invention
The present invention relates to a biochemical analysis unit and a method of producing it, and more particularly to a biochemical analysis unit used for analyzing substances derived from a living organism bound with the spot like specific-binding substances and a method of the producing thereof.
2. Description Related to the Prior Art
Recently, in biology and a medical science studies of genes are progressed. In order to analyze the genes, a radioactive labeling substance is applied as a labeling substance to a substance derived from a living organism. Thereafter the substance derived from the living organism emits a radioactive ray.
A stimulable phosphor sheet is to the substance derived from the living organism so as to absorb, store and record energies of the radioactive ray. Thus the stimulable phosphor sheet is stimulated by an electromagnetic wave having a specified wavelength. Thereafter, the stimulable phosphor can release stimulated emission into an emitted light.
In order to analyze the genes, an autoradiographic analyzing system, as known in Japanese Patent Publications No. 1-70884, 1-70882, 4-3962, is used for detecting the radioactive ray emitted from a stimulable phosphor sheet.
The autoradiographic analyzing system has merits. Unlike a system in which a photographic film is used, in the autoradiographic analyzing system, development of a chemical processing is not necessary. Further, it is possible to reproduce a desired image by effecting image processing on the obtained image data and carry out quantitative analysis by using a computer.
On the other hand, a fluorescent analyzing system is known. In the fluorescent analyzing system, a fluorescent substance is applied as the labeling substance to the substance derived from the living organism. With the fluorescent analyzing system, it is possible to study genetic sequence, the expression level of a gene, routs of metabolism, absorbance, and discharge, and to separate or identify proteins, or estimates the molecular weight or properties of the proteins or the like. As the fluorescent analyzing system, there are, for example, a western blotting method, southern blotting method and the like. In the fluorescent analyzing system, a DNA probe, which is complement to DNA containing a target gene labeled by the labeling substance, is hybridized with DNA on a transfer support. The DNA labeled by the labeling substance is combined with enzyme such that the enzyme may contact a fluorescent substance. The fluorescent substance is excited by a stimutating light to emit fluorescence, and the fluorescence is detected to produce an image and the distribution of a target DNA on the transfer support. There is a merit of the fluorescent analyzing system in which a genetic sequence or the like can be easily detected without using radioactive labeling substances.
Similarly, there is known a chemiluminescence detecting system. In the chemiluminescence detecting system is used the substance derived from a living organism that is labeled with a chemiluminescent labeling substance. The chemiluminescent labeling substance generates chemiluminescence when it contacts a chemiluminescent substrate. The chemiluminescence is detected in the wavelength of visible light to reproduce an image of the chemiluminescence on a displaying means such as a CRT or a recording material such as a photographic film. Thereby, information relating to the high molecular substance is obtained such as genetic information.
Further, a micro-array analyzing system has been recently developed for analyzing a protein such as a nucleic acid, or fragments thereof. The micro-array analyzing system comprises following steps:                (1) using a spotting device to drop specific binding substances at different positions on a surface of a carrier such as a slide glass plate, a membrane filter or the like. The specific binding substances can bind with the substance derived from a living organism such as a hormone, tumor marker, enzyme, antibody, antigen, abzyme, other protein, a nucleic acid, cDNA, DNA, RNA, or the like, whose sequence, base length, composition and the like are known;        (2) forming thereby independent spots of the specific binding substance;        (3)binding or hybridizing, in using a hybridization method, the specific binding substances with the substances which are derived from a living organism and labeled with the labeling substance such as the fluorescent substance, a dye or the like, so as to produce a micro-array;        (4)irradiating the micro-array with a stimulating ray;        (5)photoelectrically detecting light such as the fluorescence emitted from the labeling substances to generate biochemical analysis data; and        (6)analyzing the biochemical analysis data.The micro-array analyzing system has a merit in that substances derived from a living organism can be analyzed in a short time as many sorts of specific binding substances are spotted at different positions on a carrier such as a slide glass plate at high density, and further hybridized with the substance from a living organism and labeled with the labeling substances.        
Note that, in the micro-array analyzing system, a micro filtration membrane is used as the biochemical analysis unit for removing particles and bacteria. A method of producing the micro filtration membrane is disclosed in Japanese Patent Laid-open Publications No. 48-40050 and 58-37842.
Further, a macro-array analyzing system has been recently developed for analyzing a protein such as a nucleic acid, or fragments thereof. The macro-array analyzing system comprises following steps:                (1)using a spotting device to drop specific binding substances at different positions on a surface of a carrier such as a slide glass plate, a membrane filter or the like. The specific binding substances can bind with the substance derived from the living organism such as a hormone, tumor marker, enzyme, antibody, antigen, abzyme, other protein, a nucleic acid, cDNA, DNA, RNA, or the like, whose sequence, base length, composition and the like are known;        (2) forming thereby independent spots of the specific living substances;        (3)binding or hybridizing, in using a hybridization method, the specific binding substances with the substances which are derived from a living organism and labeled with the radioactive labeling substances, so as to produce a macro-array;        (4)superposing the macro-array and a stimulable phosphor sheet formed with a stimulable phosphor layer;        (5)exposing the stimulable phosphor layer to radioactive labeling substance;        (6) irradiating the stimulable phosphor layer with a stimulating ray to excite the stimulable phosphor;        (7)photoelectrically detecting the stimulated emission released from the stimulable phosphor to generate the biochemical analysis data; and        (8)analyzing the biochemical analysis data.        
In the macro-array analyzing system, when the stimulable labeling substances are exposed to the radioactive labeling substances, an electron beam (β-ray) released from the radioactive labeling substance are scattered in the carrier to impinge on a region in the stimulable phosphor layer. However, the radiation energy of the radioactive labeling substances is very large. Accordingly, the electron beams are scattered and mixed with the other electron beams emitted from the neighboring spots and then impinge on the region of the stimulable phosphor layer. Thus a noise is generated in a biochemical analysis data to make the accuracy of the biochemical analysis lower when the substances from the living organism is analyzed by quantifying the radiation amount of each spot. The accuracy of biochemical analysis is markedly degraded when spots are disposed closely to each other at high density.
Further, in the fluorescent analyzing system and the chemiluminescence detecting system, there is a similar problem. The fluorescence and the chemiluminescence are scattered in the carrier such as the membrane filter. Furthermore, the fluorescence and the chemiluminescence emitted from any particular spots is scattered and mixed with chemiluminescence or the fluorescence emitted from the neighboring spots. Accordingly, a noise is generated in the biochemical analysis data.